Pack advancer



April 1968 R. H. EICHORN 7 3,378,254

PACK ADVANCER Filed Jan. 5, 1966 6 Sheets-Sheet 1 F/GI/ INVENTOR. ROGER H. EICHQRN A TTORNEV April 16, 1968 R. H. EICHORN 3,378,254

PACK ADVANCER Filed Jan. 5, 1966 6 Sheets-Sheet 53 [7/6 2 INVENTOR.

ROGER H. EICHORN I ATTORNEY April 16, 19 68 R. H. EICHORN 3,378,254

PACK ADVANCER Filed Jan. 5, 1966 s Sheets-Sheet 5 3 Q INVENTOR. k V ROGER H. EICHORN A TTORNEV April 968 R. H. EICHORN 3,378,254

PACK ADVANCER Filed Jan. 5, 1966 6 Sheets-Sheet 4 I ROGER H.E|CHORN April 1968 R. H. EICHORN 3,378,254

PACK ADVANCER Filed Jan. 3, 1966 6 Sheets-Sheet 5 I f ".21: i

WW!!!"W INVENTOR. RQGER H. EICHORN A T TORNEV APril 968 R. H. EICHOYRN 3,378,254

PACK ADVANCER 6 Sheets-Sheet Filed Jan.

INVENTOR. ROGER H. EICHORN A TTDRNEY United States Patent Ofiice 3,378,254 Patented Apr. 16, 1968 3,378,254 PACK ADVANCER Roger H. Eichorn, Webster, N.Y., assignor to Xerox Cerporation, Rochester, N.Y., a corporation of New York Filed Jan. 3, 1966, Ser. No. 518,133 1 Claim. (Cl. 27162) ABSTRACT OF THE DISCLOSURE A tray for supporting a quantity of sheet material to be sequentially fed therefrom. The tray includes a gear sector journaled at each corner thereof rotatable by means of a rack to raise the tray so that the paper thereon is always horizontally disposed. The tray also has associated therewith, switching means including a pivotable arm coactable with the topmost sheet of the stack to actuate a motor to raise the tray so that the topmost sheet of the stack is always at a predetermined level for being fed. The tray also has, associated therewith, a finger cooperable with an aperture in the tray so as to terminate the operation of the device upon the depletion of the stack of sheet material.

This invention relates in general to sheet feeding and in particular to seriatim feeding of paper sheet material. More specifically, the invention relates to an improved paper stack advancing mechanism adapted to handle various size paper stock which automatically adjusts the material level in controlled increments to maintain a predetermined height for the separation and advancement of sheet material into an appropriate sheet advancing mechanism. This invention also provides means for terminating operation of the mechanism in which it is used when the paper stack has been depleted, lowering the advancing mechanism, thereby permitting additional sheet material to be positioned in the apparatus. For convenience of illustration, the invention is described with reference to its use in a xerographic reproducing machine. However, it is to be understood that it is not intended to be limited thereto.

It is, therefore, an object of this invention to improve pack advancers for seriatim feeding of sheet material.

It is another object of this invention to maintain the top of the pack at a predetermined height.

It is a further object of this invention to provide means for controlling machine operation when the supply of sheet material is at a predetermined minimum amount, automatically stopping the machine when the supply is depleted, and lowering the stack advancer to the proper loading level.

These and other objects are attained in accordance with the present invention wherein there is provided an adjustable pack holder adapted to maintain the level of paper stack at a predetermined height to aid in the separation and advancement of a single sheet from that height, terminating machine operation, and adapted to lower the paper tray when the paper stack is depleted.

Further objects of this invention, together with additional features contributing thereto and advantages accruing therefrom, will be apparent from the following description of an embodiment of the invention when read in conjunction with the accompanying drawings, wherein:

FIG. 1 illustrates schematically a Xerographic reproducing machine incorporating a stack advancing mechanism constructed in accordance with this invention.

FIG. 2 is an upper horizontal profile view of the stack advancer.

FIG. 3 is a vertical section view of the mechanism taken along line 3-3 of FIG. 2 to better illustrate the construction thereof.

FIG. 4 is a vertical section view taken along line 4--4 of FIG. 2.

FIG. 5 is a horizontal profile view of the adjustable stack centering mechanism.

FIG. 6 is a vertical section view of the adjusting mechataken along line 6-6 of FIG. 5 to better illustrate the construction thereof.

FIG. 7 is a perspective view of the paper feeding mechanisrn used in cooperation with the invention.

FIG. 8 is a perspective view of a paper separating device used in the invention.

FIG. 9 is a schematic diagram of the control circuit of the invention.

Referring now to the drawings, there is shown in FIG- 1 an embodiment of the subject invention in a suitable environment such as an automatic Xerographic reproducing machine. This machine comprises a xerographic plate 1 including a photoconductive layer or light-receiving surface on a conductive backing journaled in a frame to rofate in the direction indicated by the arrow to cause the plate surfac sequentially to pass a plurality of Xerographic processing stations.

For the purpose of the present disclosure, the several xerographic processing stations in the path of movement of the plate surface may be described functionally, as follows:

A charging station 2 at which a uniform electrostatic charge is deposited on or in the photoconductive layer;

An exposure station 3 at which a light or radiation pattern of copy to be reproduced is projected onto the plate surface to dissipate the charge in exposed areas thereof and thereby form a latent electrostatic image of the copy to be reproduced;

A developing station 4 at which the xerographic developing material including toner particles having an electrostatic charge opposite to that of the electrostatic latent imag are cascaded over the plate surface, whereby the toner particles adhere to the electrostatic latent image to form a xerographic powder image in the configuration of the copy being reproduced;

A transfer station 5 at which the xerographic powder image is electrostatically transferred from the plate surface to a transfer or suppo t material; and

A drum cleaning and discharge station 6 at which the plate surface is brushed to remove residual toner particles remaining thereon after image transfer, and at which the plate surface is exposed to a relatively bright light source to effect substantially complete discharge of any residual electrostatic charge remaining thereon.

It is felt that the proceeding description of the Xerographic process is sufficient for a better understanding of the disclosure of this invention.

Referring now to FlGS. 2 through 7 of the drawings, there is shown a preferred embodiment of a paper stack advancing mechanism 10 constructed in accordance with the invention.

The stack advancing mechanism 10, positioned for seriatim feeding of cut-sheet support material (usually paper) comprises an adjustable tray for holding a supply of cutsheets, a separator roller and devices for separating a single sheet of support material from the supply, feed rollers for feeding a single sheet, means for coordinating the operation of the separator rollerand feed rollers, and a paper tray level control device for raising the tray to facilitate the feeding of sheets of support material from the top of the stack.

The apparatus for feeding sheets of transfer material to the xerographic drum 1 in timed relation to the appearance of a developed image thereon includes a pair of feed rollers 201 and 202 mounted in cooperative relation to each other to direct sheets of support material forwarded by said feed rollers onto a paper transport 290 to be forwarded to the register stop 360 which functions to align and synchronize the movement of the support material with the image on the xerographic drum. For further details concerning the specific construction of this Xerographic apparatus, reference is made to copending application Ser. No. 400,363, filed on Sept. 30, 1964, in the name of Robert F. Osborne et al.

The feed roller 201 is journaled in the frame support plates of the paper transport 200, driven by means of bolts 203 of the paper transport. The feed roller 202, which is an idler roller, is journaled in cooperative relation with feed roller 201 to forward a sheet of support material advanced into the bite of the two rollers.

A supply of cut-sheet transfer material 11, typically sheets of paper or the like, to be fed one at a time to the feed rollers 201 and 202, is held in the paper tray slidably positionable from the side of the mechanism between frame plates 73 and 74. The paper tray 15 includes a base comprising three sections: a stationary base member 16, a left-hand angle member 17, and a right-hand angle member 29. The angle members 17 and 20 are each formed with upright sheet guide portions 18 and 21 and lateral portions 19 and 22 respectively, and are positioned with their upright guide portions parallel to the sides of the vase member 16 and with their lateral portions extending in a plane parallel to the base member 16.

The angle members 17 and 20 are actuable toward and away from each other by a linkage system mounted below the base member 16. As shown in FIGS. 5 and 6, the base member 16 is in a plane parallel with that of left and right lateral portions 19 and 22. Immediately below the base member 16 and in the approximate center thereof is a gear portion 25 rotatably mounted as by a pivot pin appropriately secured to the bottom of a base member 16. Two gears 27 and are rotatably mounted on the bottom of the base member 16 in cooperative relation with the gear portion 25 whereby the rotation of the gear portion will effect rotation of the two gears 27 and 30. A complementary pair of gear racks 28 and 31, slideably supported by portions 29 and 32, respectively, of the base member 16 are provided in operative relation to gear 27 and gear 30 whereby rotation of these gears will effect movement of the gear racks 28 and 31 moving the angle members 17 and 20 by means of pins 35 and 36 secured through racks 28 and 31 to the lateral portions 19 and 22 of angle members 17 and 20, respectively, for adjusting the supply holder to various sizes of paper support material.

In order to actuate the linkage thus far described, the gear portion 25 is provided with a manually actuable handle 26 which may be secured as by welding to the gear portion 25. Movement of the handle 26 in a counterclockwise direction as seen in FIG. 5 will move the angle members 17 and 20 toward each other. Movement of the angle members 17 and 20 will be in unison and equal to maintain the paper supply at a centered position.

During operation of the Xerographic apparatus, a stack of support material sheets is placed on the tray 15 and the handle 26 manipulated to bring the angle members 17 and 2% into contact with the adjacent edges of the sheets. This will ensure that the stack is centrally located within the tray and in proper alignment with the paper feed rollers. In order to remove the stack, or to replace sheets, the handle 26 is rotated in a clockwise direction which results in the angle members 17 and 20 being moved away from the center of the stack. The limit of travel of the angle members 17 and 20 will be determined by the length of the slots 37, 38, 39 and 40.

The tray 15 comprising the base member 16, the angle members 17 and 20, and the adjusting mechanism is mounted for horizontal movement as a unit toward and away from the feed rollers 201 and 202. To this end, the base member 16 is secured to the inner races 43 and 45, denoting left and right side, of a commercial type file cabinet-drawer slide. The outer races 44 and 46 for the slides are attached to spacers 47 which are mounted beneath the base member and secured to an elevating table 50. Each of the outer races 44 and 46 is secured by suitable means to the spacers 47 on the elevating table 51) and serves to support the base member 16 and linkage system relative to the elevating table 50. Suitable ball bearings mounted between the races 43 and 44, and and 46 permit slidable action between the tray 15 and the elevating table 50 and allow horizontal movement of the tray relative to the elevating table 50 to facilitate loading of sheet material. A suitable stop 13 is connected to the front of the base member 16 to ensure correct positioning of the tray 15 after loading and upon repositioning in the apparatus.

The tray 15 is also mounted for vertical movement, and to this end the elevating table 50 is provided with a left-hand and a right-hand flange 51 and 55, respectively, each flange being secured to a pair of gear sectors 52 denoting the left-hand gear sectors and 56 denoting the right-hand gear sector. Movement of the tray 15 is effected by an electric motor 60 driving gears 62 and 63 secured to shaft 64. The two gears 62 and 63 drive left and righthand gear racks 67 and 68, respectively, in a horizontal direction. The gear sectors 52 and 56 mated with the gear racks 67 and 68 are thereby moved in a path determined by vertical and horizontal slots 71 and 72 in frame plates 73 and 74, respectively. Suitable bearing supports 75 and 76 are secured to the frame plates 73 and 74 on the leftand right-hand side, respectively, to facilitate the horizontal movement of the gear racks 67 and 68. As the supply of support material is depleted from the paper tray 15, the electric motor will be actuated by means of a circuit to be hereinafter disclosed, to drive the gear racks 67 and 68 forward in the direction of paper travel, as shown in FIG. 3, through the mechanical linkage previously described. This movement of the gear racks rotates the complementary gear sectors 52 and 56 in the direction of paper travel raising the elevating table 50 in a path determined by the vertical gulde slots 71, by means of journaled pins 57 secured to the gear sectors. Movement in a vertical direction only is effectuated by the synchronous movement of the aXis of rotation 54 of each sector along the path defined by the horizontal guide slots 72 with the vertical movement of the elevating table 50.

In feeding sheets from the stack one at a time, as the topmost sheet is advanced forward, the movement of the topmost sheet will tend to advance the second sheet. In order to ensure separation of the topmost sheet only from the stack, there is provided at opposite corners of the stack, separating devices 78 and 79, as shown in FIG. 8 WhlCll apply a light-restraining force on the forward cor ners of the topmost sheet and the leading edge of the paper stack. Each of the separating devices comprises a vertically movable plunger freely movable in a tubular element secured to the outside surface of angle members 17 and 20, respectively, and movable therewith. Each of the plungers has a snubber 82 and 83, respectively, secured thereto to be positioned against the leading edge of the stack with the snubber overlying the corner of the topmost sheet. The weight of each of the plungers is imposed on the upper forward corners of the paper stack by means of the snubbers 82 and 83, and the weight on each corner is such that the plungers will follow the level of the stack downwardly as the stack level is lowered. Their weights also provide a restraining force which will assist in the feeding of a single sheet of paper when the stack is acted upon by the sheet feed mechanism to be described hereinafter. For further details concerning the specific construction of the separating devices, reference is made to copending application Ser. No. 422,657 filed Dec. 31, 1964, now Patent No. 3,288,460 in the name of R. H. Eichorn.

The lower ends of the separating devices 78 and 79 extend below the stack of support material and terminate in round ends preferably formed of nylon or Teflon. These ends are adapted to ride upon inclined plates 84 and 85 located below each separating device. As the paper tray 15 is removed from its paper feeding position, the separating devices 78 and 79 will engage the inclined plates and be raised where they will remain as the tray is retracted. With the separating devices held in their uppermost position, the snubbers 82 and 83 will be clear of the paper stack thereby permitting the addition or removal of paper sheets from the tray without encountering interference. When the tray is again moved forward into its paper feeding position, the plungers will again resume their position with the snubbers resting upon the topmost sheet.

To feed sheets of transfer material one at a time from the paper tray 15 into the bite of the feed rollers 201 and 202, there is provided a sheet feed means 410 comprising driven rollers 411 secured upon a shaft 412 journaled in bearings mounted in leftand right-hand arms 413 and 414, respectively, adapted for arcuate movement about drive shaft 415. The drive shaft 415 is driven by means of a sheet feed drive mechanism 420 not specifically disclosed herein. The sheet feed mechanism 400 comprising the sheet feed roller assembly 419 and the sheet feed drive mechanism 420 is of the type disclosed in RH. Eichorn et a1. Patent No. 3,099,943, and reference is made thereto for the details disclosed therein. However, it is to be understood that this invention is not to be limited thereto, but may be used in cooperation with various sheet feed devices.

Forward progress of the tray movement up to its operating position is determined by a stop plate 13 slida'ole in guide blocks 91 and 92 connected to the base member 16, engaging a pair of bosses 88 and 89 on stop 90. The stop plate 13 is slidahly engaged in suitable slots of lefthand and right-hand guide blocks 91 and 92, respectively, secured to upturned portions of base member 16. The stop 90 upon which bosses (i8 and 89 are mounted is secured to the frame plates 73 and 74. Upon repositioning the tray 15 into the elevating mechanism after loading a supply of sheet material, the slots in stop plate 13 engage the two bosses 83 and S9 to ensure proper alignment for feeding of the sheet material. As the supply of sheet material is depleted and the tray 15 is elevated, the engagement of the stop plate 13 with the bosses 88 and 89 prevents the elevating of the stop plate 13 with the paper tray 15. The stop plate, which is slidable in guide blocks 91 and 92 will, therefore, remain in a proper height relationship to the supply of sheet material while the paper tray is elevated. The height of the stop plate 13 is normally below that of the snubbers 82 and 83 which, as previously stated, rest upon the corners of the topmost sheet of the stack. The snubbers 32 and 83 will always occupy a position no lower than the upper edge of the stop plate 13 which must be cleared for a sheet of paper to be fed to the feed rollers 101 and 102.

In operation, as the topmost sheet is advanced by the rollers 411, the leading edge corners of the sheet engage the snubbers 82 and 83 whereupon the sheet will buckle upwardly and inwardly. As shown in FIGS. 2 and 8, the snubbers are tapered, being formed with an inner edge that is at an acute angle relative to the leading edges of the sheets of paper. As the rollers 411 apply a forward force to the topmost sheet, the forward movement of the corners lags; and as the sheet is continually advanced over the upper edge of the stop portion 13, this lag, in cooperation with the angled inner edges of the snubbers, will produce slight inward sliding movement of the corners of the sheet of paper with consequent buckling of the sheet at its middle section. This buckling action of the topmost sheet insures its separation from the underlying sheets in the stack.

As previously stated, the tray 15 is adapted for vertical movement in order to maintain the level of the stack at a relatively fixed point. This is accomplished by the use of a motor drive and a switching arrangement which will drive the tray 15 upwardly from an initial lower position when the tray supports a stack of paper to an uppermost position of the tray when only a few sheets or no sheets of paper remain in the tray.

This drive action is provided by a drive motor 61) provided with a gear reduction device 61. driving an output shaft 64 to which is secured the drive gears 62 and 63. The drive gears 62 and 63 mesh with gear racks 67 and 68, respectively, for vertical movement of the paper tray 15.

Energization of the motor 69 is under control of a paper level limit switch LS-l, a low paper limit switch LS-Z, and a shut down switch LS-3. The paper level switch LS-l is mounted on a connecting rod 94 which extends across the tray above the level of the stack and is secured to the frame plates 73 and 74. This switch is provided with an arm 96 adapted to contact the stack level for actuating the switch into its open and closed positions. Normally, the paper level switch LS-1 is in its closed position when no force is applied upon the arm 96; however, when the level of the stack reaches a predetermined height, the top of the stack engage the arm to actuate the switch LS-l to its open condition, thus de-energizing the motor 68.

As shown in the illustrative schematic circuit diagram of FIG. 9, the switch LS-l is connected in series with the motor 60 and a suitable door interlock switch LS4, which is in a closed condition when the door 98 of the base section for the apparatus is closed. When the top of the stack is below the predetermined level, the motor 6% will be energized through the normally closed contacts of LS1 until the top of the stack reaches the predetermined level, whereupon the switch LS-l will be actuated to its open position for de-energizing the motor.

A low paper limit switch LS2, is secured to frame plate 74 in a position to be contacted by gear rack 68 when the gear rack has moved to its forwardmost position which indicates that the paper tray 15 has been advanced to its uppermost height.

As the tray is moved upwardly when paper is being fed out of the tray 15 under the power produced by the motor 60 and as controlled by the paper level determining switch LS-1, the gear rack 68 is moved forward. This occurs as the paper stack becomes gradually depleted through use of the Xerographic apparatus. When the paper tray 15 contains only a few sheets of paper, the gear rack 68 will contact the low paper limit switch LS-Z closing its contacts and actuating a warning light to indicate the supply of sheet material is depleted.

A shut down switch LS3 is provided to terminate operation of the copying mechanism in which the apparatus of this invention is used by energizing a timer shown in FIG. 9 to time out the machine after the last sheet has been fed from the paper tray. The switch LS3, mounted on tie rod 94, is provided with an arm 93 which rests on the top of the stack of sheet material. Upon the feeding of the last sheet, the arm will fall through a slot 23 in base member 16 of the paper tray 15 closing the normally open contacts LS-3a to energize the timer to terminate operation of the mechanism and opening the normally closed contacts LS-3b to prevent further operation of the motor 69. With the printing apparatus shut down, the operation of the xerographic apparatus terminates until paper is added to the tray 15.

In order to lower the tray 15 for permitting an operator to add paper, the paper feed mechanism also includes a mechanical interlock device between the door 98 to the printing apparatus and the tray 15. The mechanical interlock device comprises a ratchet bar 151 secured to rack support plate 152 as by welding and to an angle bar support 153 which extends the width of the support plate. A bell crank 156 rotatably secured to an angle bracket 154 supported on the rack support plate 15?. is biased in a clockwise direction, as seen in FIG. 3, by means of a torsion spring, with its pawl arm 157 engaging the ratchet to permit only unidirectional movement of the gear racks when the pawl is engaging the ratchet bar. In operation, as the motor 60 drives the drive gears 62 and 63 advancing the gear racks 67 and 68 and rack support plate 152 to elevate the paper tray 15, the pawl arm 157 of the bell crank 156 advances over the ratchet bar 151 preventing the paper tray from lowering. When the stack of paper held on the paper tray has become exhausted, resulting in the termination of machine op eration, the operator opens the door 98 of the apparatus which automatically lowers the paper tray. Lowering of the paper tray is effectuated by the rotation of pawl arm 157 of the bell crank 156 out of engagement with the ratchet bar 151 thus enabling the paper tray to lower under its own weight. The bell crank 156 is rotated by means of an adjustable linkage 160 secured to the door at one end by means of a bracket 161. The other end of the adjustable linkage is connected to a pin 162 secured to arm 158 of the bell crank engaging a slot 163 in the adjustable linkage. As the door is opened, the linkage rotates the bell crank pawl out of engagement with the ratchet bar thus lowering the paper tray. Two springs 99 each secured at one end to pins 69 and 70, respectively, of frame plates 73 and '74, respectively, and at the other ends to gear sectors 52 and 56, respectively, prevent rapid lowering of the paper tray and the resulting impact. When the operator has replenished the depleted supply of paper, the door is then closed effectuating the rotation of the pawl 157 of bell crank 156 into engagement with the ratchet bar 151. Suitable locks, shown as magnetic catches 97, are provided on the door to prevent accidental opening of the door 98 thereby interrupting the machine operation.

While the invention has been described with reference to the structure disclosed herein, it is not confined to the details set forth in this application. It is intended to cover such modifications or changes as may come within the purpose of the improvements or the scope of the following claim.

What is claimed is:

1. A pack advancer for use in cooperation with a sheet feed mechanism to maintain a stack of sheet material at a predetermined height including support means for containing a stack of sheet material,

rotatable gear sectors each having first pins extending through said sectors perpendicular to the plane of rotation of said sectors, each of said sector having second pins parallel to said first pins journaled for rotation in said sectors and said support means,

first slots to constrain said first pins for movement in a horizontal plane,

second slots to constrain said second pins and said support means for movement in vertical planes,

a gear rack operatively coupled with each gear sector to rotate said gear sectors to effect horizontal motion of said first pins and vertical movement of said second pins and said support means to thereby raise sheet material contained on said support means,

drive means operatively connected to said gear racks for movement thereof,

an electrical circuit connected to said drive means and to a source of electric power, and

switching means connected in said circuit for controlling energization of said drive means, said switching means including a pivo-table arm adapted to coact with the topmost sheet of the stack for energizing said drive means to elevate said tray and to de-energize said drive means when the topmost sheet reaches a predetermined level, said switching means also including a finger adapted to coact with an aperture in said support means when the stack of sheet material has been depleted to thereby terminate the operation of the pack advancer.

References Cited UNITED STATES PATENTS 759,558 5/11904 Scott 2546.6 3,097,760 7/1963 Short 271-62 3,301,551 1/1967 tCassano 27162 FOREIGN PATENTS 433,914 9/ 1926 Germany.

RICHARD E. AEGERTER, Primary Examiner. 

